Big Upgrade of Microsoft DOS System
Microsoft on Tuesday released MS-DOS 5.0, the newest version of its 10-year-old operating system software for IBM and compatible PCs. The program is perhaps the most significant upgrade in the history of DOS, particularly because it allows you more space in your computer’s memory to run programs.
The new version also offers on-line help, has commands that can “undelete” files, “unformat” disks and comes with a much better manual than previous versions.
An operating system is the basic software that controls the overall operation of the computer.
The most significant advantage of DOS 5.0 is the way it manages random-access memory (RAM) on PCs with Intel 286, 386 and 486 microprocessors. You need a machine with one of those microprocessors to take advantage of DOS 5.0’s improved ability to manage memory.
Those machines can be equipped with vast amounts of memory, but most software programs can only run in the first 640 kilobytes, called conventional memory. Previous versions of DOS occupied from 60 kilobytes to 70 kilobytes of that memory so there was less room for other software, a condition known as “RAM cram.”
The new version of DOS is able to load all but 19 kilobytes of itself into the first 64 kilobytes of extended memory (called the “high memory area”) that resides outside the main 640-kilobyte area. That leaves more room for other programs in conventional memory.
Users of 386 and 486 machines get yet another advantage. DOS 5.0 can also run memory resident programs--including software required for using a mouse or accessing a local area network--outside of the first 640 kilobytes. On my 386 machine, I’ve loaded DOS, a mouse driver and several other memory resident programs yet still have about 610 kilobytes left over to run other programs.
Freeing up that 640 kilobytes is a boon to users of multitasking software such as Microsoft Windows. Windows is now able to run several large DOS programs--each using as much as 610 kilobytes of conventional memory. Windows and programs designed specifically for Windows runs in extended memory.
The new version of DOS will also work with older style PCs with 8088 or 8086 central processing units. In these cases, DOS will occupy about 64 kilobytes of main memory, but you’ll still have enough left over to run most programs. Users of such systems who believe that they suffer from RAM cram should seriously consider upgrading their hardware.
Memory management isn’t the only advantage of 5.0. The new DOS comes with an improved DOS shell. Shell is an interface that shields you from having to use DOS’ arcane display and commands. Instead of having to type commands, you interact with the computer using the mouse (or arrow keys) and pull-down menus. You get a graphical view of your files and directories and can use the mouse to drag files from one directory to another or to copy, delete or rename a file or directory. You can run programs by clicking on their name or selecting them from a menu.
The shell can also serve as a “task switcher,” allowing you to keep two or more programs in memory at a time. That allows you to jump between programs without having to unload the software you’re currently using. DOS finally has an on-line help facility. You can read about a command by preceding it with HELP. Typing HELP DIR, for example, tells you the different ways to display a list of files. On that subject, you can now display files sorted by date, name, size or extension.
DOS now comes with some useful utility programs that were previously only available at an extra cost. One program, Undelete, will restore erased files. Another, called Unformat, can restore data to disks that were accidentally reformatted.
These data recovery programs don’t work in every situation, but there is a reasonable chance you’ll be able to restore a deleted file if you use the undelete program immediately after the file is erased. For a more reliable unerase program, you should get Norton Utilities 6.0 from Symantec or PC Tools from Central Point Software.
There is now a memory resident program, called Doskey, which allows you to view, edit and reissue commands that you have used previously during the session.
DOS now comes with an easy-to-use text editor as well as an updated version of the BASIC programming language. Both BASIC and the new editor work with a mouse and have pull-down menus.
Upgrading to the new DOS is easy. You turn on the machine, insert a floppy disk, type setup and follow the instructions. There is even a program to “uninstall” DOS 5.0 and return to your previous version in the unlikely event that you’re unhappy with the upgrade.
There is generally some risk associated with being an early adopter of a new operating system, but Microsoft has improved the odds by issuing pre-release copies to about 7,000 “beta testers.” I’ve spent two months working with a preliminary copy and, so far, I’m quite impressed.
DOS 5.0 upgrade kits (retail price $99.95) are available from software dealers and mail-order companies. Organizations with more than one machine can purchase upgrade licenses for $79.95 (retail). Microsoft has established a toll-free DOS 5.0 information line at (800) 992-DOS5.
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